1) Bully 2) Molester 3) More than a pest 4) Persecutor 5) Persistent annoyer 6) Pesky sort 7) Tormenter 8) Tormentor 1) Harrier 2) Pest 
• (n.) One who harasses.
Har'ass·er (-ẽr) noun One who harasses. 
[n] - a persistent attacker
harass, harassing, harassment, harasser 1. To persistently annoy, to attack, or to bother somebody. 2. To impede and exhaust an enemy by attacking repeatedly or with repeated raids. 3. To irritate or to torment persistently. 4. To wear out; to exhaust. Historical origin of harass and its various forms Just about everyone has been harassed at o...